Aeronautical propeller



Nov. 22, 1927. 1,650,464

' 5. A. REED AERONAUT I CAL PROPELLER Original Filed June 22, 1922 EYEN QR ATTORNEY atented Nov. 22, 1927.

NITED STATES v 1,650,464 PATENT ounce.

SYLVANUS A. REED, OF NEW YORK, N. Y., ASSIGNOR TO THE REED PROPELLEB GO.

ING, OF NEW YORK, Y., A CORPORATION OF NEW YORK.

AERONAUTICAL PROPELLER.

flontinuation of application Serial No. 570,139, filed June 22, 1922. This application filed May 12, 1924, Serial No. 712,644, and in France May 81, 1923.

united at the hub or shaft. My present invention refers to multiple blade construction in which I use separate blades united with each other at the hub or shaft, the means of blade junction being applicable not only to two blade propellers, but also to three blades, four blades or any desired number.

There are advantages of fabrication in the separate blade propellers, mainly concerned in the greater ease and economy of forging, but also in the assembly of three, four and other numbers of blades into a unit. Previous ways of connecting separate blades to I a central drive-shaft applied to propellers and rotary fans or blowers, unite the blades to a central hub which is interposed between the blades. In my invention, I unite the blades to each other direct and use a central hub, boss or shaft attachment only to transmit torque and thrust, and having no share in supporting the radial tension due to centrifugal force. In the operation of aeronautical propellers, the rates of rotation and the propeller diameters and weights are such Wt that centrifugal force is far the largest stress which the central portion has to sustain, and in my. novel plan of uniting the separate blades direct to each other thus relieves the shaft-attaching means from the principal working stress. In my preferred form of central blade junction my novel method of blade construction also leaves the root portions of the blades at the proper angles for the pitch, and dispenses with a central reversing twist or series of bends, which is necessary in single-piece propellers of this type, when made interchangeable with the usual wood propellers on the same steel hub. My preferred form also accommodates contrated a propeller with separable blades vemently, a pair of filler blocks or bosses B supplying the central hole and the fore and aft flat circular surfaces and bolt-holes adapted for attachment of the steel hubs in general use, and these bosses when finally bolted within the assembled blades are then adapted .to be mounted on an ordinary metal hub, not herein shown.

Other features of the invention will be hereinafter referred to.

In the drawings, in which a number 0 embodiments of the invention have been selected for illustration:

Fig. 1, is an edge view of a form of propeller embodying my invention.

Fig. '2, is a view in cross-section of the propeller shown in Fig. 1.

Fig. 3, is a face view of a propeller em.- bodving another form of the invention.

ig. 4,, is a face view of one of the detached propeller blades shown in Fig. 3.

Fig. 5, is a View of one of the detached blades shown in Fig. l, showing the other side and edge thereof.

' Figs. 6 and 7, show inside and outside views, respectively, of the pair of fillerblocks or members used at the central bladejunction. Fig. 8, shows a modification.

Referring to the drawings for a more detailed description of the invention, in the form shown in Figs. 1 and 2, the blade fork- -prongs and 2O, and 21 and 22, of the respectivef blades 10 and 11, are elongated and have their outer ends bent into hooks substantially at right-angles tothe prongs, and these. hooks are placed in inter-locking ar-- rangement in direct contact and are bolted together by bolts 23. The space between the prongs provides the central opening 24, for the reception of the drive shaft or hub, the

forks straddling such part as in the other form, the shaft being indicated at 18, Fig. 2.

Asthe blades at their inner parts are deformed, filler blocks 25 and 26, are employed upon the opposite sides to accommodate such deformation. By the use of slots 27, in the hooked ends of the blades, for the passage of the bolts 23, I am enabled to adjust the blades to change their pitch if desired.

, In Figs. 3 to 7, I show a three-blade construction of propeller having separate blades 30, 31 and 32, each with its inner end forked so as to provide the interlockin pron 33 and 34, which are made in hook orm wifii the beak of the hooks lyin upon opposite sides of the blade. These ooks are set at different blade-positioning angles and considering the blade 30, and noting that the blades are arranged at a third of a circle apart, its hook 34 is interlocked with the adjacent hook on blade 31, while its other hook 33, is interenga ed with the adjacent hook on blade 32, an the remaining hook on each of the blades 31 and 32, engage each other, as will be understood from Fig. 3. Bolts 35 are passed through each pair of the interengaging hooks, and the structure thus made a unit comprising the blades and bolts. The notches between the prongs 33 and 34, provide the desired central opening 36, throu h which the hub or shaft is passed, and whic part is spanned or straddled by the notched inner ends of the blades. The hooks are bent to an acute angle to the blade and the lines of the bends form obtuse angles with the edges of the blade beyond the ends. These blade-positioning angles are calculated so that when the three blades are interlocked the faces of the forks will lie together in coincidence and the nclination of the blades to the plane of rotation will be at the particular angle desired for the particular blade pitch designed. In this union of the three blades, it will be seen that the forked prolongation of the leading edge of each blade interengages with the forked prolongation of the trailing edge of the adjacent blade.

Each of the hooks of the blades may be provided with slots 37, for the passage of the binding bolts 35, so that by loosening the bolts each blade may be adjusted on its longitudinal .axis so as to change the pitch, if desired, the bolts being then tightened to retain the adjustment.

In Figs. 6 and 7, are shown a pair of filler members or blocks 38' and 39, which are applied to the opposite sides of the central junction of the blades, the one having its contacting face provided with projections 40 and the other having its contacting face provided with similar projections, which are shaped to conforin to the inclined blade parts at the central junction where they are interhooked with each other. The exterior faces of the respective blocks are flat and circular, and each block is formed with a central perforation 42, which registers with the central opening 36, of the assembled blades. A series of bolt holes 43, formed longitudinally through each of said blocks are in alinement with each other and register with bolt-holes 44, formed at the inner ends of the respective blades, and when bolts are passed through these several holes and secured witli nuts, the filler blocks are securely clamped against the opposite sides of the inter-engaging blades and adapted to be mounted on an ordinary steel-hub,

not herein shown. The filler. blocks are made of aluminium or any suitable light weight material which will serve the purpose of providing strong clamping means adapted for mounting the ordinary steel hubs.

While the filler blocks shown in Figs. 6 and 7, are formed. for co-o eration with a three-blade construction as s own in Fig. 3, blocks 44 and 45, for a two-blade construction may be employed, as shown in Fig. 8, and these blocks may be modified to accommodate any other desired number of interengaging separable blades. The two blades 10 and 11" shown in Fig. 8, have the forkrongs at their inner ends made into overapping hooks 46 and 47, which may be formed with slots 48 and 49, res ectively, through which bolt 50 passes, and y means of which the parts are secured together in adjustable relation which permits of each blade being turned slightly on its longitudinal axis to alter the pitch-an le thereof. These adjusting slots may be ma e either in one or both of the blade fork-prongs as desired; In the event that the blades are designed for adjustment of the position thereof, the filler blocks 38 and 39 are mounted -to provide spaces between the blades and adjacent faces of the blocks, any such spaces that are left when the adjustment is made being filled with thin shim pieces, wedges, or the like which may be used as needed to fill in new spaces formed when the blade angles are changed. When the spaces have thus been filled the bolts passing through the parts are ti htened thegeby clamping the hub pieces tightly toet er. g In the constructions shown the central united formation is adapted for mounting on the conventional steel hub for wooden propellers and which have a shaft-embracing sleeve and two flanges and the two and three blade units described may therefore be inter-changeable with convenizliogal wooden propellers on the same steel This application in respect to the construction shown in Figs. 1 and 2,'is a continuation of my said Patent No. 1,518,410 granted Dec. 9, 1924. The construction and formation of the respective blades herein shown and their pitch-angles may be carried out in accordance with my said patents.

I wish to be understood as not limiting my invention to the particular forms of construction herein shown, as it is evident that various modifications may be made in the several parts thereof, without, however, departing from the spirit of my invention.

In cases where the slots and bolts are employed to alter the pitch-angles of the separate blades, the bolt holes of the filler blocks and also blades require a slight adjustment to provide for the changed angle, or interchangeable filler-blocks may be used. In making in separable blade propeller, I find that excel ent results are obtained by using light-Weight metal alloys, particularly aluminum alloys, such for example,- as duralumin.

What I claim is f 1. An aeronautical propeller having separable blades capable of being adjusted angularly on their longitudinal axes, said blades having forked root portions whereby the fork prong portions may be placed in straddled relation to a propeller shaft and in overlapping adjustable relation to each other, and means for attaching the overlapping prong portions together and permitting the angular adjustment of said blades on their longitudinal axes.

2. An aeronautical propeller having separable blades displaceable around their longitudinal axes and'provided with hook members at their rootportions, said hook members being formed to be placed in interengaging relation to hold the blades in operating position, and means carried by said hook-members for permitting displacement of said blades/around their longitudinal axes.

3. An aeronautical propeller having separable blades capable of being adjusted angularly on their longitudinal axes and provided with laterally extending hook members at the blade root portions, the hook members of one blade being formed to be placed in interengaging relation with the hook members of another blade, and adjustablemeans for fastening the interen aged hook members together, said means eing mounted on said hook members and operating to permit the angular adjustment of said blades on their longitudinal axes.

a. An aeronautical propeller having separable blades capable of being adjusted angularly on their longitudinal axes and provided with forked prong root portions whereby the fork prong members may be placed in straddled relation to a propeller shaft, and the prong members on each blade being bent laterally in opposite directions whereby the prong members of one blade may be placed in adjustable interengaging relation with the prong members of another. and means mounted on said hook prong members for permitting the angular adjustment of said blades on their longitudinal axes.

5. An aeronautical propeller having separable blades displaceable around their longitudinal axes and provided with forked prong root portions whereby the fork prong members may be placed in straddled, relation to a propeller shaft, and the prong members on each blade being bent laterally in apposite directions whereby the prong membersrof one blade may be placed in adjustable interengaging relation with the prong members of another, and means mounted on said prong members for perhas two base terminal forked elongationsbent in opposite directions overlapping and interengaging with the adjacent corresponding blade e-longaitions at a desired pitch angle, the interengaging portions provided with means to maintain them rigidly in position, and operating to permit the angular adjustment bf said blades on their longitudinal axes.

7. An aeronautical propeller having blades directly and rigidly connected together at their bases which connection sustains the entire stress of centrifugal force, and shaft attaching means to transmit torque and thrust, each blade of which propeller has two base terminal forked elongations bent in opposite directions overlapping and interengaging with the adjacent corresponding blade elongations at a desired pitch angle, and filler pieces fitting one on the forward and the other on the rearward side of the assembled blades at the center of the ropeller, said filler pieces having faces and olt holes formed for attachment to forward and rearward hub flanges 8. An aeronautical propeller having separable blades formed at their inner ends with integral extensions directly interengaging each other, said extensions being disposed at certain blade-positioning angles.

9. An aeronautical propeller provided with separate blades capable of being adjusted angularly on their longitudinal axes and having their inner ends or root portions provided with prongs constructed and arranged so that When the blades are assembled the space between said prongs provides a passage for a driving member, and said prongs of one blade overlapping those of another, one upon one side of the blade and one upon the other, and means for securing the parts together in adjustable relation, said means being carried by said prongs.

10. An aeronautical propeller having separable blades provided at their inner ends with interengaging hooked parts having bolt-receiving slots, and bolts arranged in said slots, whereby the pitch-angles of the blades may be changed.

11. An aeronautical propeller having sepa:

rate blades and having their root portions provided with prongs projecting outwardly Mild at interengaging acute anglesfor positioning tions, said prongs projecting outwardly at the blades when assembled, the prongs of interengaging acute angles, the engaging face one blade being formed to be placed in mterof each prong disposed on a plane oblique 10 engaging relation with the prongs of another to the median plane of its blade. 5 blade. In testimony whereof, I have hereunto set 12. An aeronautical propeller having sepamy hand. rate blades provided with pronged root por- SYLVAN US A. REED. 

